The present invention is directed to a duplex strainer and, in particular, to a duplex strainer having an improved flow diverter mechanism.
Duplex strainers have been developed in order to permit continuous straining and cleaning of a flow. Duplex strainers generally include two strainer chambers and some type of mechanism for diverting the flow from one chamber to the other to permit cleaning, servicing or repairing of one chamber while the other one is in use. This permits the flow through the duplex strainer to remain continuous.
One such duplex strainer is known in the art described in U.S. Pat. No. 4,496,463 which includes a unitary housing with an inlet port and an outlet port. A first and second strainer chamber, each having first and second ports, are in separate fluid communication with the housing. A scotch yoke design converts rotation of a first shaft into reciprocal lateral displacement of first and second disc assemblies to permit either the first or second strainer chamber to be closed off to flow while the other of the first or second strainer chambers remain open to flow.
Another design of the duplex strainer consists of two cylindrical plugs or one tapper plug as transfer valve and having one piece body casting. Such a duplex strainer has been satisfactory for its intended application, however, it suffers from the disadvantages that the casting of a unitary piece body is difficult. Furthermore, it is difficult to effect a tight seal with the sleeve and it was impossible to perform in-line repairs upon the strainer. Accordingly, it is desired to provide an improved duplex strainer which overcomes the disadvantages of the prior art design.